Add previousStatus in MemberRemoved, see #3252
Config of cluster info logging, see #3225
fix some warts in IO

- remove TcpPipelineHandler’s type parameter
- remove not-accept() failure test (which is completely bogus)
- add comments explaining more about TcpPipelineHandler.Init
- remove the funny “manager” from the Server example
Remove experimental label from cluster, see #3283
Validate deployment paths at startup, see #2749
ClusterSingletonManagerSpec must not use 'node' from other thread, see #3382

* Thank you @rkuhn for finding the reason for the problem
* Sprinkled some warnings
Start heartbeatSender after Welcome, see #3388

* Otherwise, if the Welcome message is lost, other nodes
  in the cluster will send HeartbeatRequest and it will start
  sending heartbeats without being a real member and the lost Welcome
  is not detected by the other members in the cluster
 #3378 - fixing memory leak in LARS.stop
add BackpressureBuffer, see #3253

- also make a Write’s “ack” be a Tcp.Event (to suit pipelines)
- add stress test for BackpressureBuffer
- add it to SslTlsSupportSpec
- add it to the docs
add ScalaDocs and correct UDP docs, see 3268
split IO docs and mark them EXPERIMENTAL, see #3294
fix one more warning
Merge pull request #1471 from akka/wip-3252-MemberRemoved-patriknw

Add previousStatus in MemberRemoved, see #3252
Merge pull request #1472 from akka/wip-3225-cluster-infolog-patriknw

Config of cluster info logging, see #3225
Merge pull request #1474 from akka/wip-3283-non-experimental-cluster-patriknw

Remove experimental label from cluster, see #3283
Merge pull request #1476 from akka/wip-2749-validate-deploy-patriknw

Validate deployment paths at startup, see #2749
Merge pull request #1479 from akka/wip-3382-ClusterSingletonManagerSpec-patriknw

ClusterSingletonManagerSpec must not use 'node' from other thread, see #3382
Merge pull request #1480 from akka/wip-3388-HeartbeatReq-patriknw

Start heartbeatSender after Welcome, see #3388
Change default tick-duration to 10ms, see #3387
Include path in error message for missing router conf, see #3178